Papillary thyroid carcinoma (PTC) comprises 90% of all cases of thyroid cancer. Thyroid cancer is now the 4th or 5th most common cancer in women in Western Countries and more than 71,000 patients in North America will be treated this year. Treatment of PTC typically requires a total thyroidectomy followed by radioactive iodine treatment to remove small deposits of residual tumor. Clinicians rely on criteria such as tumor size and clinical presentation to predict the risks of metastatic disease.
However, these measures are inaccurate in over 30% of cases and patients with larger indolent tumors can be over treated while aggressive smaller tumors with a high propensity for metastases are undertreated. In addition, more than 40% of PTC patients exhibit some degree of resistance to adjuvant radioiodine therapy due to down-regulation of the sodium-iodide symporter (NIS) that is responsible for iodine uptake in thyroid cells. These patients ultimately have higher rates of recurrent disease and a poorer prognosis.
Accordingly, there is a need for a method to effectively treat PTC that restores radioiodine sensitivity to PTC cells to eliminate or greatly reduce PTC.